An improved self-aligning scale assembly was invented by Benny N. Dillon, to whom this application is assigned, and is described in application Ser. No. 527,325, filed Aug. 29, 1983 and entitled SELF-ALIGNING SCALE ASSEMBLY AND METHOD. This scale assembly includes a platform which is supported by a plurality of force transmitting assemblies. The force transmitting assemblies and platform cooperate to automatically center the platform relative to an enclosing structure and to align the force transmitting assemblies and platform. The automatic centering of the platform and aligning of the force transmitting assemblies is accomplished by moving the platform back and forth in sideways directions. Centering the platform and aligning the force transmitting assemblies is effective to eliminate sideward force components on load cells in the force transmitting assemblies.
Each force transmitting assembly in the aforementioned scale assembly includes a support member which may be the arm of a load cell, a slider and a force transmitting member. In one embodiment of the scale assembly invented by Mr. Dillon, the force transmitting member is a rocker pin having an upper end portion disposed in a recess in the load cell arm and a lower end portion disposed in a recess in the slider. The load cell arm and slider are relatively movable from an aligned position through a range of offset positions to any one of a plurality of maximum offset positions.
When the load cell arm and slider are in a maximum offset position, the side of the rocker pin is disposed in abutting engagement with the side of the recess in the load cell arm. This results in the rocker pin and slider being held against movement relative to the load cell arm. Therefore, continued movement of the platform relative to the base results in movement of the slider relative to the base.
Although the aforementioned scale assembly is generally satisfactory in its mode of operation and represents a substantial improvement over prior scale assemblies, there may be a tendency for the load transmitting member or pin to slide relative to the load cell arm when the force transmitting assembly is in a maximum offset condition. In addition, the recess in the load cell arm must be accurately machined so that the rocker pin will engage the side of the recess when a predetermined amount of relative movement has occurred between the platform and slider.